X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/95ee0ac83bdbd235d2094bd4e638a9dfd49f5583..5aad18a52bd34084e11c13753204c03aa3ff1686:/src/common/imagpng.cpp diff --git a/src/common/imagpng.cpp b/src/common/imagpng.cpp index 11655cf352..ca4e72c240 100644 --- a/src/common/imagpng.cpp +++ b/src/common/imagpng.cpp @@ -1,5 +1,5 @@ ///////////////////////////////////////////////////////////////////////////// -// Name: imagepng.cpp +// Name: src/common/imagepng.cpp // Purpose: wxImage PNG handler // Author: Robert Roebling // RCS-ID: $Id$ @@ -7,30 +7,33 @@ // Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// -/* - We don't put pragma implement in this file because it is already present in - src/common/image.cpp +// ============================================================================ +// declarations +// ============================================================================ -#ifdef __GNUG__ -#pragma implementation "image.h" -#endif -*/ +// ---------------------------------------------------------------------------- +// headers +// ---------------------------------------------------------------------------- // For compilers that support precompilation, includes "wx.h". #include "wx/wxprec.h" #ifdef __BORLANDC__ -#pragma hdrstop + #pragma hdrstop +#endif + +#ifndef WX_PRECOMP + #include "wx/defs.h" #endif -#include "wx/image.h" +#if wxUSE_IMAGE && wxUSE_LIBPNG + +#include "wx/imagpng.h" #include "wx/bitmap.h" #include "wx/debug.h" #include "wx/log.h" #include "wx/app.h" -#if wxUSE_LIBPNG -#include "../png/png.h" -#endif +#include "png.h" #include "wx/filefn.h" #include "wx/wfstream.h" #include "wx/intl.h" @@ -45,188 +48,559 @@ #endif #endif -#ifdef __WXMSW__ -#include -#endif +// ---------------------------------------------------------------------------- +// constants +// ---------------------------------------------------------------------------- + +// image can not have any transparent pixels at all, have only 100% opaque +// and/or 100% transparent pixels in which case a simple mask is enough to +// store this information in wxImage or have a real alpha channel in which case +// we need to have it in wxImage as well +enum Transparency +{ + Transparency_None, + Transparency_Mask, + Transparency_Alpha +}; -//----------------------------------------------------------------------------- -// wxPNGHandler -//----------------------------------------------------------------------------- +// ---------------------------------------------------------------------------- +// local functions +// ---------------------------------------------------------------------------- + +// return the kind of transparency needed for this image assuming that it does +// have transparent pixels, i.e. either Transparency_Alpha or Transparency_Mask +static Transparency +CheckTransparency(unsigned char **lines, + png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h, + size_t numColBytes); + +// init the alpha channel for the image and fill it with 1s up to (x, y) +static unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y); + +// find a free colour for the mask in the PNG data array +static void +FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height, + unsigned char& rMask, unsigned char& gMask, unsigned char& bMask); + +// is the pixel with this value of alpha a fully opaque one? +static inline +bool IsOpaque(unsigned char a) +{ + return a == 0xff; +} + +// is the pixel with this value of alpha a fully transparent one? +static inline +bool IsTransparent(unsigned char a) +{ + return !a; +} -#if wxUSE_LIBPNG +// ============================================================================ +// wxPNGHandler implementation +// ============================================================================ -#if !USE_SHARED_LIBRARIES IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler) + +#if wxUSE_STREAMS + +#ifndef PNGLINKAGEMODE + #if defined(__WATCOMC__) && defined(__WXMSW__) + // we need an explicit cdecl for Watcom, at least according to + // + // http://sf.net/tracker/index.php?func=detail&aid=651492&group_id=9863&atid=109863 + // + // more testing is needed for this however, please remove this comment + // if you can confirm that my fix works with Watcom 11 + #define PNGLINKAGEMODE cdecl + #else + #define PNGLINKAGEMODE LINKAGEMODE + #endif #endif -#if wxUSE_STREAMS -static void _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length ) +// VS: wxPNGInfoStruct declared below is a hack that needs some explanation. +// First, let me describe what's the problem: libpng uses jmp_buf in +// its png_struct structure. Unfortunately, this structure is +// compiler-specific and may vary in size, so if you use libpng compiled +// as DLL with another compiler than the main executable, it may not work +// (this is for example the case with wxMGL port and SciTech MGL library +// that provides custom runtime-loadable libpng implementation with jmpbuf +// disabled altogether). Luckily, it is still possible to use setjmp() & +// longjmp() as long as the structure is not part of png_struct. +// +// Sadly, there's no clean way to attach user-defined data to png_struct. +// There is only one customizable place, png_struct.io_ptr, which is meant +// only for I/O routines and is set with png_set_read_fn or +// png_set_write_fn. The hacky part is that we use io_ptr to store +// a pointer to wxPNGInfoStruct that holds I/O structures _and_ jmp_buf. + +struct wxPNGInfoStruct +{ + jmp_buf jmpbuf; + bool verbose; + + union + { + wxInputStream *in; + wxOutputStream *out; + } stream; +}; + +#define WX_PNG_INFO(png_ptr) ((wxPNGInfoStruct*)png_get_io_ptr(png_ptr)) + +// ---------------------------------------------------------------------------- +// helper functions +// ---------------------------------------------------------------------------- + +extern "C" { - ((wxInputStream*) png_get_io_ptr( png_ptr )) -> Read(data, length); + +void PNGLINKAGEMODE wx_PNG_stream_reader( png_structp png_ptr, png_bytep data, + png_size_t length ) +{ + WX_PNG_INFO(png_ptr)->stream.in->Read(data, length); } -static void _PNG_stream_writer( png_structp png_ptr, png_bytep data, png_size_t length ) +void PNGLINKAGEMODE wx_PNG_stream_writer( png_structp png_ptr, png_bytep data, + png_size_t length ) { - ((wxOutputStream*) png_get_io_ptr( png_ptr )) -> Write(data, length); + WX_PNG_INFO(png_ptr)->stream.out->Write(data, length); } -bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream ) +// from pngerror.c +// so that the libpng doesn't send anything on stderr +void +PNGLINKAGEMODE wx_png_error(png_structp WXUNUSED(png_ptr), png_const_charp message) { - // VZ: as this function uses setjmp() the only fool proof error handling - // method is to use goto (setjmp is not really C++ dtors friendly...) - - unsigned char **lines; - unsigned int i; - png_infop info_ptr = (png_infop) NULL; - - image->Destroy(); - - png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING, - (voidp) NULL, - (png_error_ptr) NULL, - (png_error_ptr) NULL ); - if (!png_ptr) - goto error_nolines; - - info_ptr = png_create_info_struct( png_ptr ); - if (!info_ptr) - goto error_nolines; - - if (setjmp(png_ptr->jmpbuf)) - goto error_nolines; - - if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) - goto error_nolines; - - png_set_read_fn( png_ptr, &stream, _PNG_stream_reader); - - png_uint_32 width,height; - int bit_depth,color_type,interlace_type; - - png_read_info( png_ptr, info_ptr ); - png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL ); - - if (color_type == PNG_COLOR_TYPE_PALETTE) - png_set_expand( png_ptr ); - - png_set_strip_16( png_ptr ); - png_set_packing( png_ptr ); - if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS)) - png_set_expand( png_ptr ); - png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER ); - - image->Create( width, height ); - - if (!image->Ok()) - goto error_nolines; - - lines = (unsigned char **)malloc( height * sizeof(unsigned char *) ); - if (lines == NULL) - goto error_nolines; - - for (i = 0; i < height; i++) + wxLogFatalError( wxString::FromAscii(message) ); +} + +void +PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message) +{ + wxPNGInfoStruct *info = png_ptr ? WX_PNG_INFO(png_ptr) : NULL; + if ( !info || info->verbose ) + wxLogWarning( wxString::FromAscii(message) ); +} + +} // extern "C" + +// ---------------------------------------------------------------------------- +// LoadFile() helpers +// ---------------------------------------------------------------------------- + +// determine the kind of transparency we need for this image: if the only alpha +// values it has are 0 (transparent) and 0xff (opaque) then we can simply +// create a mask for it, we should be ok with a simple mask but otherwise we +// need a full blown alpha channel in wxImage +// +// parameters: +// lines raw PNG data +// x, y starting position +// w, h size of the image +// numColBytes number of colour bytes (1 for grey scale, 3 for RGB) +// (NB: alpha always follows the colour bytes) +Transparency +CheckTransparency(unsigned char **lines, + png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h, + size_t numColBytes) +{ + // suppose that a mask will suffice and check all the remaining alpha + // values to see if it does + for ( ; y < h; y++ ) { - if ((lines[i] = (unsigned char *)malloc(width * (sizeof(unsigned char) * 4))) == NULL) + // each pixel is numColBytes+1 bytes, offset into the current line by + // the current x position + unsigned const char *ptr = lines[y] + (x * (numColBytes + 1)); + + for ( png_uint_32 x2 = x; x2 < w; x2++ ) { - for ( unsigned int n = 0; n < i; n++ ) - free( lines[n] ); - goto error; + // skip the grey or colour byte(s) + ptr += numColBytes; + + unsigned char a2 = *ptr++; + + if ( !IsTransparent(a2) && !IsOpaque(a2) ) + { + // not fully opaque nor fully transparent, hence need alpha + return Transparency_Alpha; + } } + + // during the next loop iteration check all the pixels in the row + x = 0; + } + + // mask will be enough + return Transparency_Mask; +} + +unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y) +{ + // create alpha channel + image->SetAlpha(); + + unsigned char *alpha = image->GetAlpha(); + + // set alpha for the pixels we had so far + png_uint_32 end = y * image->GetWidth() + x; + for ( png_uint_32 i = 0; i < end; i++ ) + { + // all the previous pixels were opaque + *alpha++ = 0xff; } - - // loaded successfully! + + return alpha; +} + +void +FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height, + unsigned char& rMask, unsigned char& gMask, unsigned char& bMask) +{ + // choosing the colour for the mask is more + // difficult: we need to iterate over the entire + // image for this in order to choose an unused + // colour (this is not very efficient but what else + // can we do?) + wxImageHistogram h; + unsigned nentries = 0; + unsigned char r2, g2, b2; + for ( png_uint_32 y2 = 0; y2 < height; y2++ ) + { + const unsigned char *p = lines[y2]; + for ( png_uint_32 x2 = 0; x2 < width; x2++ ) + { + r2 = *p++; + g2 = *p++; + b2 = *p++; + + wxImageHistogramEntry& + entry = h[wxImageHistogram:: MakeKey(r2, g2, b2)]; + + if ( entry.value++ == 0 ) + entry.index = nentries++; + } + } + + if ( !h.FindFirstUnusedColour(&rMask, &gMask, &bMask) ) + { + wxLogWarning(_("Too many colours in PNG, the image may be slightly blurred.")); + + // use a fixed mask colour and we'll fudge + // the real pixels with this colour (see + // below) + rMask = 0xfe; + gMask = 0; + bMask = 0xff; + } +} + +// ---------------------------------------------------------------------------- +// reading PNGs +// ---------------------------------------------------------------------------- + +bool wxPNGHandler::DoCanRead( wxInputStream& stream ) +{ + unsigned char hdr[4]; + + if ( !stream.Read(hdr, WXSIZEOF(hdr)) ) + return false; + + return memcmp(hdr, "\211PNG", WXSIZEOF(hdr)) == 0; +} + +// convert data from RGB to wxImage format +static +void CopyDataFromPNG(wxImage *image, + unsigned char **lines, + png_uint_32 width, + png_uint_32 height, + int color_type) +{ + Transparency transparency = Transparency_None; + + // only non NULL if transparency == Transparency_Alpha + unsigned char *alpha = NULL; + + // RGB of the mask colour if transparency == Transparency_Mask + // (but init them anyhow to avoid compiler warnings) + unsigned char rMask = 0, + gMask = 0, + bMask = 0; + + unsigned char *ptrDst = image->GetData(); + if ( !(color_type & PNG_COLOR_MASK_COLOR) ) { - int transp = 0; - png_read_image( png_ptr, lines ); - png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL ); - unsigned char *ptr = image->GetData(); - if ((color_type == PNG_COLOR_TYPE_GRAY) || - (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + // grey image: GAGAGA... where G == grey component and A == alpha + for ( png_uint_32 y = 0; y < height; y++ ) { - for (unsigned int y = 0; y < height; y++) + const unsigned char *ptrSrc = lines[y]; + for ( png_uint_32 x = 0; x < width; x++ ) { - unsigned char *ptr2 = lines[y]; - for (unsigned int x = 0; x < width; x++) + unsigned char g = *ptrSrc++; + unsigned char a = *ptrSrc++; + + // the first time we encounter a transparent pixel we must + // decide about what to do about them + if ( !IsOpaque(a) && transparency == Transparency_None ) { - unsigned char r = *ptr2++; - unsigned char a = *ptr2++; - if (a < 128) + // we'll need at least the mask for this image and + // maybe even full alpha channel info: the former is + // only enough if we have alpha values of 0 and 0xff + // only, otherwisewe need the latter + transparency = CheckTransparency + ( + lines, + x, y, + width, height, + 1 + ); + + if ( transparency == Transparency_Mask ) { - *ptr++ = 255; - *ptr++ = 0; - *ptr++ = 255; - transp = 1; + // let's choose this colour for the mask: this is + // not a problem here as all the other pixels are + // grey, i.e. R == G == B which is not the case for + // this one so no confusion is possible + rMask = 0xff; + gMask = 0; + bMask = 0xff; } - else + else // transparency == Transparency_Alpha { - *ptr++ = r; - *ptr++ = r; - *ptr++ = r; + alpha = InitAlpha(image, x, y); } } + + switch ( transparency ) + { + case Transparency_Mask: + if ( IsTransparent(a) ) + { + *ptrDst++ = rMask; + *ptrDst++ = bMask; + *ptrDst++ = gMask; + break; + } + // else: !transparent + + // must be opaque then as otherwise we shouldn't be + // using the mask at all + wxASSERT_MSG( IsOpaque(a), _T("logic error") ); + + // fall through + + case Transparency_Alpha: + if ( alpha ) + *alpha++ = a; + // fall through + + case Transparency_None: + *ptrDst++ = g; + *ptrDst++ = g; + *ptrDst++ = g; + break; + } } } - else + } + else // colour image: RGBRGB... + { + for ( png_uint_32 y = 0; y < height; y++ ) { - for (unsigned int y = 0; y < height; y++) + const unsigned char *ptrSrc = lines[y]; + for ( png_uint_32 x = 0; x < width; x++ ) { - unsigned char *ptr2 = lines[y]; - for (unsigned int x = 0; x < width; x++) + unsigned char r = *ptrSrc++; + unsigned char g = *ptrSrc++; + unsigned char b = *ptrSrc++; + unsigned char a = *ptrSrc++; + + // the logic here is the same as for the grey case except + // where noted + if ( !IsOpaque(a) && transparency == Transparency_None ) { - unsigned char r = *ptr2++; - unsigned char g = *ptr2++; - unsigned char b = *ptr2++; - unsigned char a = *ptr2++; - if (a < 128) + transparency = CheckTransparency + ( + lines, + x, y, + width, height, + 3 + ); + + if ( transparency == Transparency_Mask ) { - *ptr++ = 255; - *ptr++ = 0; - *ptr++ = 255; - transp = 1; + FindMaskColour(lines, width, height, + rMask, gMask, bMask); } - else + else // transparency == Transparency_Alpha { - if ((r == 255) && (g == 0) && (b == 255)) r = 254; - *ptr++ = r; - *ptr++ = g; - *ptr++ = b; + alpha = InitAlpha(image, x, y); } + + } + + switch ( transparency ) + { + case Transparency_Mask: + if ( IsTransparent(a) ) + { + *ptrDst++ = rMask; + *ptrDst++ = bMask; + *ptrDst++ = gMask; + break; + } + else // !transparent + { + // must be opaque then as otherwise we shouldn't be + // using the mask at all + wxASSERT_MSG( IsOpaque(a), _T("logic error") ); + + // if we couldn't find a unique colour for the + // mask, we can have real pixels with the same + // value as the mask and it's better to slightly + // change their colour than to make them + // transparent + if ( r == rMask && g == gMask && b == bMask ) + { + r++; + } + } + + // fall through + + case Transparency_Alpha: + if ( alpha ) + *alpha++ = a; + // fall through + + case Transparency_None: + *ptrDst++ = r; + *ptrDst++ = g; + *ptrDst++ = b; + break; } } } - - for ( unsigned int j = 0; j < height; j++ ) - free( lines[j] ); - free( lines ); - - if (transp) - { - image->SetMaskColour( 255, 0, 255 ); - } - else + } + + if ( transparency == Transparency_Mask ) + { + image->SetMaskColour(rMask, gMask, bMask); + } +} + +// temporarily disable the warning C4611 (interaction between '_setjmp' and +// C++ object destruction is non-portable) - I don't see any dtors here +#ifdef __VISUALC__ + #pragma warning(disable:4611) +#endif /* VC++ */ + +bool +wxPNGHandler::LoadFile(wxImage *image, + wxInputStream& stream, + bool verbose, + int WXUNUSED(index)) +{ + // VZ: as this function uses setjmp() the only fool proof error handling + // method is to use goto (setjmp is not really C++ dtors friendly...) + + unsigned char **lines = NULL; + png_infop info_ptr = (png_infop) NULL; + wxPNGInfoStruct wxinfo; + + wxinfo.verbose = verbose; + wxinfo.stream.in = &stream; + + image->Destroy(); + + png_structp png_ptr = png_create_read_struct + ( + PNG_LIBPNG_VER_STRING, + (voidp) NULL, + wx_png_error, + wx_png_warning + ); + if (!png_ptr) + goto error; + + // NB: please see the comment near wxPNGInfoStruct declaration for + // explanation why this line is mandatory + png_set_read_fn( png_ptr, &wxinfo, wx_PNG_stream_reader); + + info_ptr = png_create_info_struct( png_ptr ); + if (!info_ptr) + goto error; + + if (setjmp(wxinfo.jmpbuf)) + goto error; + + png_uint_32 i, width, height; + int bit_depth, color_type, interlace_type; + + png_read_info( png_ptr, info_ptr ); + png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL ); + + if (color_type == PNG_COLOR_TYPE_PALETTE) + png_set_expand( png_ptr ); + + // Fix for Bug [ 439207 ] Monochrome PNG images come up black + if (bit_depth < 8) + png_set_expand( png_ptr ); + + png_set_strip_16( png_ptr ); + png_set_packing( png_ptr ); + if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS)) + png_set_expand( png_ptr ); + png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER ); + + image->Create((int)width, (int)height, (bool) false /* no need to init pixels */); + + if (!image->Ok()) + goto error; + + lines = (unsigned char **)malloc( (size_t)(height * sizeof(unsigned char *)) ); + if ( !lines ) + goto error; + + for (i = 0; i < height; i++) + { + if ((lines[i] = (unsigned char *)malloc( (size_t)(width * (sizeof(unsigned char) * 4)))) == NULL) { - image->SetMask( FALSE ); + for ( unsigned int n = 0; n < i; n++ ) + free( lines[n] ); + goto error; } } - - return TRUE; - - error_nolines: - lines = NULL; // called from before it was set - error: - wxLogError(_("Couldn't load a PNG image - probably file is corrupted.")); - + + png_read_image( png_ptr, lines ); + png_read_end( png_ptr, info_ptr ); + png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL ); + + // loaded successfully, now init wxImage with this data + CopyDataFromPNG(image, lines, width, height, color_type); + + for ( i = 0; i < height; i++ ) + free( lines[i] ); + free( lines ); + + return true; + +error: + if (verbose) + wxLogError(_("Couldn't load a PNG image - file is corrupted or not enough memory.")); + if ( image->Ok() ) { image->Destroy(); } - + if ( lines ) { free( lines ); } - + if ( png_ptr ) { if ( info_ptr ) @@ -237,87 +611,224 @@ bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream ) else png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL ); } - return FALSE; + return false; } +// ---------------------------------------------------------------------------- +// writing PNGs +// ---------------------------------------------------------------------------- -bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream ) +bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose ) { + wxPNGInfoStruct wxinfo; + + wxinfo.verbose = verbose; + wxinfo.stream.out = &stream; + + png_structp png_ptr = png_create_write_struct + ( + PNG_LIBPNG_VER_STRING, + NULL, + wx_png_error, + wx_png_warning + ); + if (!png_ptr) { - png_structp png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); - if (!png_ptr) - { - return FALSE; - } - - png_infop info_ptr = png_create_info_struct(png_ptr); - if (info_ptr == NULL) - { - png_destroy_write_struct( &png_ptr, (png_infopp)NULL ); - return FALSE; - } - - if (setjmp(png_ptr->jmpbuf)) - { - png_destroy_write_struct( &png_ptr, (png_infopp)NULL ); - return FALSE; - } - - png_set_write_fn( png_ptr, &stream, _PNG_stream_writer, NULL); - - png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8, - PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE, - PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); - - png_color_8 sig_bit; - sig_bit.red = 8; - sig_bit.green = 8; - sig_bit.blue = 8; - sig_bit.alpha = 8; - png_set_sBIT( png_ptr, info_ptr, &sig_bit ); - png_write_info( png_ptr, info_ptr ); - png_set_shift( png_ptr, &sig_bit ); - png_set_packing( png_ptr ); - - unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 ); - if (!data) - { - png_destroy_write_struct( &png_ptr, (png_infopp)NULL ); - return FALSE; - } - - for (int y = 0; y < image->GetHeight(); y++) + if (verbose) + wxLogError(_("Couldn't save PNG image.")); + return false; + } + + png_infop info_ptr = png_create_info_struct(png_ptr); + if (info_ptr == NULL) + { + png_destroy_write_struct( &png_ptr, (png_infopp)NULL ); + if (verbose) + wxLogError(_("Couldn't save PNG image.")); + return false; + } + + if (setjmp(wxinfo.jmpbuf)) + { + png_destroy_write_struct( &png_ptr, (png_infopp)NULL ); + if (verbose) + wxLogError(_("Couldn't save PNG image.")); + return false; + } + + // NB: please see the comment near wxPNGInfoStruct declaration for + // explanation why this line is mandatory + png_set_write_fn( png_ptr, &wxinfo, wx_PNG_stream_writer, NULL); + + const int iColorType = image->HasOption(wxIMAGE_OPTION_PNG_FORMAT) + ? image->GetOptionInt(wxIMAGE_OPTION_PNG_FORMAT) + : wxPNG_TYPE_COLOUR; + const int iBitDepth = image->HasOption(wxIMAGE_OPTION_PNG_BITDEPTH) + ? image->GetOptionInt(wxIMAGE_OPTION_PNG_BITDEPTH) + : 8; + + wxASSERT_MSG( iBitDepth == 8 || iBitDepth == 16, + _T("PNG bit depth must be 8 or 16") ); + + bool bHasAlpha = image->HasAlpha(); + bool bHasMask = image->HasMask(); + bool bUseAlpha = bHasAlpha || bHasMask; + + int iPngColorType; + if ( iColorType==wxPNG_TYPE_COLOUR ) + { + iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_RGB_ALPHA + : PNG_COLOR_TYPE_RGB; + } + else + { + iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_GRAY_ALPHA + : PNG_COLOR_TYPE_GRAY; + } + + png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), + iBitDepth, iPngColorType, + PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, + PNG_FILTER_TYPE_BASE); + + int iElements; + png_color_8 sig_bit; + + if ( iPngColorType & PNG_COLOR_MASK_COLOR ) + { + sig_bit.red = + sig_bit.green = + sig_bit.blue = (png_byte)iBitDepth; + iElements = 3; + } + else // grey + { + sig_bit.gray = (png_byte)iBitDepth; + iElements = 1; + } + + if ( iPngColorType & PNG_COLOR_MASK_ALPHA ) + { + sig_bit.alpha = (png_byte)iBitDepth; + iElements++; + } + + if ( iBitDepth == 16 ) + iElements *= 2; + + png_set_sBIT( png_ptr, info_ptr, &sig_bit ); + png_write_info( png_ptr, info_ptr ); + png_set_shift( png_ptr, &sig_bit ); + png_set_packing( png_ptr ); + + unsigned char * + data = (unsigned char *)malloc( image->GetWidth() * iElements ); + if ( !data ) + { + png_destroy_write_struct( &png_ptr, (png_infopp)NULL ); + return false; + } + + unsigned char * + pAlpha = (unsigned char *)(bHasAlpha ? image->GetAlpha() : NULL); + int iHeight = image->GetHeight(); + int iWidth = image->GetWidth(); + + unsigned char uchMaskRed = 0, uchMaskGreen = 0, uchMaskBlue = 0; + + if ( bHasMask ) + { + uchMaskRed = image->GetMaskRed(); + uchMaskGreen = image->GetMaskGreen(); + uchMaskBlue = image->GetMaskBlue(); + } + + unsigned char *pColors = image->GetData(); + + for (int y = 0; y != iHeight; ++y) + { + unsigned char *pData = data; + for (int x = 0; x != iWidth; x++) { - unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3); - for (int x = 0; x < image->GetWidth(); x++) + unsigned char uchRed = *pColors++; + unsigned char uchGreen = *pColors++; + unsigned char uchBlue = *pColors++; + + switch ( iColorType ) { - data[(x << 2) + 0] = *ptr++; - data[(x << 2) + 1] = *ptr++; - data[(x << 2) + 2] = *ptr++; - if ((data[(x << 2) + 0] == image->GetMaskRed()) && - (data[(x << 2) + 1] == image->GetMaskGreen()) && - (data[(x << 2) + 2] == image->GetMaskBlue())) - { - data[(x << 2) + 3] = 0; - } - else + default: + wxFAIL_MSG( _T("unknown wxPNG_TYPE_XXX") ); + // fall through + + case wxPNG_TYPE_COLOUR: + *pData++ = uchRed; + if ( iBitDepth == 16 ) + *pData++ = 0; + *pData++ = uchGreen; + if ( iBitDepth == 16 ) + *pData++ = 0; + *pData++ = uchBlue; + if ( iBitDepth == 16 ) + *pData++ = 0; + break; + + case wxPNG_TYPE_GREY: + { + // where do these coefficients come from? maybe we + // should have image options for them as well? + unsigned uiColor = + (unsigned) (76.544*(unsigned)uchRed + + 150.272*(unsigned)uchGreen + + 36.864*(unsigned)uchBlue); + + *pData++ = (unsigned char)((uiColor >> 8) & 0xFF); + if ( iBitDepth == 16 ) + *pData++ = (unsigned char)(uiColor & 0xFF); + } + break; + + case wxPNG_TYPE_GREY_RED: + *pData++ = uchRed; + if ( iBitDepth == 16 ) + *pData++ = 0; + break; + } + + if ( bUseAlpha ) + { + unsigned char uchAlpha = 255; + if ( bHasAlpha ) + uchAlpha = *pAlpha++; + + if ( bHasMask ) { - data[(x << 2) + 3] = 255; + if ( (uchRed == uchMaskRed) + && (uchGreen == uchMaskGreen) + && (uchBlue == uchMaskBlue) ) + uchAlpha = 0; } + + *pData++ = uchAlpha; + if ( iBitDepth == 16 ) + *pData++ = 0; } - png_bytep row_ptr = data; - png_write_rows( png_ptr, &row_ptr, 1 ); } - - free(data); - png_write_end( png_ptr, info_ptr ); - png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr ); + + png_bytep row_ptr = data; + png_write_rows( png_ptr, &row_ptr, 1 ); } - return TRUE; + + free(data); + png_write_end( png_ptr, info_ptr ); + png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr ); + + return true; } -#endif // wxUSE_STREAMS -#endif +#ifdef __VISUALC__ + #pragma warning(default:4611) +#endif /* VC++ */ -// wxUSE_LIBPNG +#endif // wxUSE_STREAMS +#endif // wxUSE_LIBPNG